Artificial leg connection



March 19, 1940.. s. E. FORSTER ARTIFICIAL LEG CONNECTION Filed Jan. 16,1959 INVENTO Guy E Forsfer Patented Mar. 19, 1940 UNITED STATES PATENTOFFICE I ARTIFICIAL LEG CONNECTION I Guy E. Forster, Cincinnati, OhioApplication January 16, 1939, Serial No. 251,057

t1" Y 4 Claims.

The invention has reference to an artificial limb connection, andparticularly to the improvement of the connection between an upper-legstump socket part and a body band, belt, or' other "5 suspension meansfor the socket part.

An object of the invention is to provide improvements in an artificiallimb structure whereby the breakage of parts, wear, noise, and frequentservicing are reduced to a minimum, or obviated entirely.

Another object is to greatly facilitate the wearers efforts to simulatenatural leg and body movements, and to accomplish this by meansv of asimpler, rather than a more complex, alteration in construction.

Another object of the invention is the provision of improved means ofthe character stated, whereby much of the discomfort and inconvenienceof wearing an artificial limb are effectively minimized, especially byeliminating chafing, pinching and distortion of the wearer's body in thevarious body postures and movements.

A further object of the invention is to greatly simplify and reduce thecost of artificial limb structures, as well as the cost andinconvenience of frequent servicing and adjustments. The tightening andlubricating of the parts have been eliminated entirely.

The foregoing and other objects are attained 5 by the means describedherein and disclosed in the accompanying drawing, in which:

Fig. 1 is a side elevational View showing the invention applied to thebody of a wearer in standing position. v

Fig. 2 is a view showing the relationship of the device to the wearersbody when in a sitting or stooped position.

Figs. 3 and 4 are elevational views showing the relationship of theparts when the trunk of the body is turned or pivoted to the right, andto the left, respectively.

Fig. 5 is an enlarged cross-sectional view taken on line 55 of Fig. 3. 1Fig. 6 is a fragmental perspective view of '4 limb connection means ofthe invention.

the

It has been customary and usual in the past,

to support an artificial limb part, such as a thigh section 8, from abelt, band or other body harness member applied to the body in theregion of the hips, waist, or pelvic region; An

sented various problems that have been more or less a source ofannoyance" and expense to the person who was required to make use of anartificial limb. For example, the use of metal pivots and links resultedin squeaks and rattles due to the parts becoming worn and loose, andwhen such conditions occurred it was necessary for the user to have theparts tightened or replaced. Another inconvenience was that the devicerequired frequent lubrication, and this of course resulted in soilingthe clothing. Metal pivots and links in the limb structure had atendency also to chafe and pinch the Wearers body under certainconditions, and would not ordinarily permit the freedom of movement thatwas considered desirable but unattainable in an artificial limbstructure.

Prior to the present invention, various improvements were made for thepurpose of en- 'hancing the flexibility of use of the artificial limb,but at the expense of reducing the qualities of durability and freedomfrom breakage and frequent servicing. Such improvements embraced the useof leather straps for connecting the limb part to a body harness, andwhen such straps were anchored to prevent pivoting nove ment thereof atthe body harness, strains were imposed across the width of the strapstending to stretch one side edge and compress the other side edge, sothat the material of the straps was soon torn and required replacement.instances, a plurality of flexible straps were used, the lower ends ofwhich were secured at spaced intervals along the top of the artificiallimb part, but such constructions were objectionable in that some of thestraps were tensioned .while the others were buckled up in anobjectionable manner when the wearer assumed seated or stoopedpositions. Both the tensioned and the buckled straps resulted indiscomfort to the wearers body in the region of the hips and thighs.

The various principal objections above referred'to, as well as otherminor objections not worthy of mention, have been efiectively over-'come by means of theimproved construction of artificial limb connectionherein disclosed.

With reference to the accompanying drawing, 8 indicates the thigh partof an artificial limb, and I0 and I2 indicate the lower leg and footportions. These parts 8, l0, and I2 are suitably .reticulatedor hingedin accordance with com- In some .3

mon practice. The means usually employed for control of the parts I andI2 while walking, have been omitted from the disclosure for the reasonthat they form no essential part of the present invention. The wearersleg stump is indicated at I3 and as will be understood, same is suitablysupported within the hollow socket portion of the thigh part, the usualpadding being employed for the wearers comfort.

The harness part 9 may be of leather, fabric, or other suitable materialproperly padded and shaped to fit either the waist or the pelvic regionof the wearers body. The harness is adapted to support a curved brace orstrap 2! of rigid material, which may be light weight metal or anequivalent thereof. The brace 2| may be fixed to the harness in anysuitable manner, such as by means of rivets, bolts, or the like I4. Thebrace is adapted to carry an adjustable pressure clamp part IS, theexact nature of which will be treated hereinafter.

To the outer face of the thigh part 8, there is fixed a base plate 22which likewise has an adjustable clamp part II. The base plate may bescrewed or otherwise fixed to the thigh element 8, as indicated by thedrawing.

In accordance with the invention, the connection between the harness andthe base plate of the thigh part, is effected by means of a bar l8molded or otherwise shaped from resilient soft rubber or any rubber likematerial that may be considered an equivalent of resilient soft rubberfor the purpose of this disclosure. It is important that the bar l8 beof substantial thickness, such as to impart thereto the characteristicsof flexibility in all directions laterally, together with limitedstretchability and high though yielding resistance to lengthwisecompressibility. T0 attain these characteristics, the bar of resilientsoft rubber may be made cylindrical or slightly oval in cross section,with a mean diameter approximating 1", more or less. The bar |8 may beseveral inches in length but the length thereof will be determined bythe build or physique of the wearer of the artificial limb.

In the preferred form of the invention, the soft rubber bar E8 ispendant substantially vertical from the harness, and only one such baris employed, by preference. The advantage of this is readily appreciatedwhen referring to Figs. 2, 3, and 4, which show the ease with which thesoft rubber bar or connector will accommodate itself to movements of thewearers trunk relative to the artificial leg part 8. It will be notedfrom Fig. 2, that the soft rubber connector accommodates itself towhatever position is required for enabling the wearer to sit or stoop,or otherwise bend his body below the abdomen. It should be notedparticularlythatnostrains or cutting tendencies will be experienced bythe wearer exemplified by Fig. 2, such as would be bound to occur withthe use of strap connectors that would be drawn taut or would buckleunder the same conditions.

With further reference to Fig. 2, it is important to note that there isnothing to prevent the wearer from swinging his artificial limb sidewisein a horizontal plane with absolute freedom to do so. This is a movementwhich cannot be accomplished where the limb structure is constituted ofpivoted metallic parts.

Fig. 3 shows a desired distorted condition of the soft rubber barconnector, resulting from the wearer turning or pivoting the trunk ofhis body to the right, without changing the position of his artificialleft leg. It should be noted that the effort to so pivot the body willbe no more than is required of a person having a natural left leg, andthe natural tendency of the resilient bar is to return the trunk tonormal position relative to the thigh portion of the leg, just as themuscles of a natural leg would operate. The same advantages are notedwhen the wearers trunk is turned or pivoted to the left, withoutshifting the movements of the artificial left leg.

Due to the fact that the unusual thickness of the soft rubber connectingbar imparts thereto a yielding resistance compressible lengthwise, thebar acts as a shock absorber for upward forces resulting from contact ofthe foot upon the pavement with each successive step of the walkingfunction. For the same reason, lengthwise stretchability of theconnecting bar is quite limited, so that there may be no tendency forthe leg stump to move in the leg socket and thereby chafe the skin ofthe leg stump. In other words, there is just suflicient pressure betweenthe leg stump and the artificial leg socket to furnish a sensation ofcomfort, as the pressure upon the stump resulting from walking, isalternately relieved without actual relative movement between the legstump and the socket of the artificial limb part Another advantageincident to the use of the resilient soft rubber like material in aconnecting bar of substantial proportions as described, is the ease withwhich the upper and lower portions H3 and 20 thereof may be secured tothe brace 2| and plate 22, respectively. As herein disclosed, it isnecessary only to squeeze the opposite ends of the soft rubber bartightly against the parts and 22 by means of simple clamping elements land I6 so that said ends cannot shift or move, thereby obviating wear atthe anchorages, and eliminating all need for lubrication and subsequenttightening. It will be evident, of course, that the structure cannotpossibly develop squeaks or rattles at any location.

The clamping elements I5 and I6 may be identical. and each may comprisesimply a metallic rigid strap having perforate ears 23 and 24 and acurved intermediate portion adapted to tightly squeeze or pinch the endof the soft rubber bar to ensure absolute fixation thereof. It isconsidered preferable, though not absolutely necessary to furnish screwthreaded means for drawing the clamp part tightly upon the end portionof the soft rubber bar, and to this end, the perforations of the ears 23and 24 may be caused to register with similar perforations in the brace2|, thereby enabling the introduction of a screw 25 whose shank maythreadedly engage a nut 28 at the back of the brace. The head of thescrew, as well as a portion of the nut, may be counter-sunk in themetallic parts to avoid objectionable projecting parts, and to enhancethe appearance of the device in general. The nut 26 where exposed at theback of the brace 2|, may be of hexagon or other shape so as toaccommodate a wrench if and when required during application of theclamp part. As clearly indicated in Fig. 5, the upper and lower edges ofthe clamp parts may be flared or rounded so as to eliminate anypossibility of cutting into or wearing away of the areas of the softrubber bar adjacent to the clamping areas. In the less expensive formsof the device, the screw arrangement 25-26 may be replaced by rivets orother fastening means, if desired.

It is noteworthy that the rigid clamping of the opposite'end portions ofthe bar does not interfere with twisting of the soft rubber bar axially,to

enable the wearer to point the toe of the artificial limb eitherinwardly or outwardly and, in fact, the

wearer may accomplish without undue effort, any leg movement that he maybe wishful or able to accomplish by skillful control of the leg stump.Such accomplishments are not readily permissible when the artificiallimb is supported by means of metallic links and pivots, or straps thattightly tension or buckle in the various natural positions I assumed bythe wearers body.

As previously stated, the invention'is intended to comprehend the use ofrubber substitutes and rubber compositions in formation of the bar l8,and the cross-sectional shape of the rubber bar is immaterial so long asthe thickness thereof .is substantial in comparison with the thicknessof an ordinary leather strap with relation to its width. Various othermodifications and changes may be made in the structural details of thedevice, within the scope of-, the appended claims,

without departing from the spirit of the invention.

I claim:

1. In an artificial limb, structure, the combination of a thigh part,and a suspension means lengthwise, said bar having upper and lowerportions fixed, respectively, to the body harness and the thigh part oftheartificial limb structure in an upright position.

2. In an artificial limb bination of a thigh part, and a suspensionmeans therefor comprising a harness adapted to be structure, thecomcarriedby the body of a wearer, and a connector between the thighpart and the harness, said connector comprising a bar of resilient softrubber material of a substantial thickness such as to impart thereto thecharacteristics of flexibility in all directions laterally, togetherwith limited stretchability and high. though yielding resistance tocompressibility lengthwise, saidbar having opposite resilient laterallycompressible end portions, and-means on the harness and the thigh partfor clampingsaid compressible end portions securely against movement andresultant wear and noise, thereby imposing upon the intermediate portionof the bar substantially all the burden of flexion due to use of theartificial limb.

3. An assembly for attachment to an artificial limb, which assemblycomprises a bar of flexible and resilient material of a substantialthickness such as to impart thereto the characteristics of flexibilityin all directions laterally, together with limited stretchability andhigh though yielding resistance to lengthwise compressibility, said barhaving opposite ends, a body brace of substantially rigid material andmeans thereon for tightly clamping one 'end of the bar against relativemovement, a base plate for attachment to a limb, and means for tightlyclamping the other end of the bar in fixed relation to the base plate.

4. An assembly for attachment to an artificial limb, which assemblycomprises abar of flexible and resilient material of a substantialthickness 7 such as to impart thereto the characteristics of flexibilityin all directions laterally, together with limited stretchabilityandhigh though yielding resistance to lengthwise compressibility, saidbar having opposite ends, a body brace and means thereon for tightlyclamping one-end of the bar against relative movement, and means forsecuring the other end of the bar in fixed relation to an artificialleg.

GU OR ER.

